1. Field of the Invention
This invention relates to an automatic gain control circuit, and more particularly it pertains to an automatic gain control circuit for recording systems or the like including two, left and right, channels, which is so designed as to ensure that the characteristics of the two channels always be substantially equal to each other.
2. Description of the Prior Art
In such a type of circuit, there is a tendency that difference in gain control effect occurs between the two channels due to deviations in the base-emitter voltage versus base current characteristics and internal resistances of the transistors constituting the circuit. In the case of two-channel stereo equipment, for example, the above-mentioned difference in gain control effect should be eliminated since it is desired that no difference in characteristics be present between the two channels.
To cope with the foregoing problem, it has heretofore been the usual practice to adopt a circuit arrangement such as one which will be described hereinafter with reference to FIG. 1 of the accompanying drawings. With such a conventional circuit arrangement, however, it was not possible to achieve a satisfactory correcting effect. The reason for this will also be explained hereinafter.